Payloads carried aboard launch vehicles can vary widely as to size, function and system requirements. For example, a space shuttle orbiter of the National Space Transportation System (NSTS) can be equipped to carry, in its payload bay, configurations of Spacelab, developed by the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA). Spacelab is modularly configured and can be varied to meet specific mission requirements. Spacelab can include a pressurized module containing a laboratory, one or more open pallets that expose materials and equipment to space, a tunnel for accessing the pressurized module, and/or an instrument pointing subsystem. An orbiter cargo also could include, for example, one or more deployable spacecraft, medium-sized payloads and/or small self-contained payloads known as “getaway specials”.
Payloads typically utilize a high percentage of limited launch vehicle capability and resources, e.g. weight, payload bay and/or fairing volume, avionics and/or power. Launch vehicle resource allocation and payload integration are complicated by the fact that launch vehicle customers frequently have unusual individual needs for payload services such as power, monitoring/commanding, attitude/pointing, contamination control, fluid services and active cooling. Thus, preparing payloads for flight and for integration with a launch vehicle usually is a lengthy and complicated process.
For most reusable launch vehicle missions, payload requirements are accommodated by reconfiguring the launch vehicle payload bay. Avionics, software and other systems also are reconfigured in accordance with new payload configurations and needs. Detailed compatibility analyses are commonly performed to ensure that the reconfigured systems function as needed for both launch vehicle and payload(s).
Payloads for space shuttle flights are processed through a series of facilities and testing procedures, and launch vehicle modifications also are subjected to testing. It typically becomes necessary to reconfigure payload ground handling equipment to process payloads at one or more payload processing facilities. Additionally, small non-deployable payloads to be mounted in a vehicle payload bay sidewall cannot be installed until relatively late in the integration process. Thus the time required to integrate payloads with a launch vehicle can be lengthy and subject to change. It would be desirable to eliminate the need to reconfigure a payload bay and ground handling equipment for each launch vehicle flight. It also would be desirable to reduce payload integration costs and timelines.